powerpc/qspinlock: don't propagate the not-sleepy state

To simplify things, don't propagate the not-sleepy condition back down
the queue. Instead, have the waiters clear their own node->sleepy when
finding the lock owner is not preempted.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Tested-by: Shrikanth Hegde <sshegde@linux.vnet.ibm.com>
Reviewed-by: "Nysal Jan K.A" <nysal@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231016124305.139923-5-npiggin@gmail.com